A new book which claims that Christians are the victims of worldwide persecution has stirred controversy in Italy amid accusations that it minimises the Holocaust and demonises Islam.

The author, Antonio Socci, claims the untold story of the 20th century is the murder of 45 million Christians, mostly at the hands of communist and Islamic regimes, and that massacres continue to this day.

The New Persecuted, Inquiries into Anti-Christian Intolerance in the New Century of Martyrs, has angered some scholars by depicting Christians as beleaguered victims of rampaging Muslims.

Some reviewers have hailed the publication as a wake-up call to Christians in the west who have not realised, even in the wake of September 11, that they are under attack by a hostile rival religion.

Others said Mr Socci was part of a rightwing revisionist effort to distort history and promote a hawkish response to perceived threats.

Drawing heavily from the World Christian Encyclopedia, published last year by the Oxford University Press, Mr Socci traces the persecution of Christians through the centuries, from the crucifixion of Jesus to the lions at Circus Maximus, the assassination of Thomas Becket and the execution of Thomas More, the Boxer rebellion in China, Mexico's revolution and the Turkish massacres in Armenia. He calculates that in the past 2,000 years some 70 million Christians have been killed, two-thirds in the past 100 years alone, a bloodbath blamed mostly on the Soviet Union as well as communist China and Nazi Germany.

Mr Socci supports Israel and does not dispute the number of Jews killed in the Holocaust but by framing the genocide in such a context he had minimised its significance, said Alberto Melloni, an author and religious historian.

"The statistics he cites are largely meaningless but the effect is to make the Shoah [Holocaust] just one detail in a century of massacres. It is part of an effort by some in the Catholic church to stop the Shoah being the most important event in the 20th century."

Mr Socci, 43, a columnist with conservative Italian newspapers, claims that an average of 160,000 Christians have been killed every year since 1990, the vast majority in the third world. Critics said the figure included Christians killed in conflicts which had little to do with religion.

Chronicling attacks, pogroms and wars in East Timor, Indonesia, Sudan, Egypt, Pakistan, India, and even Rwanda and Latin America, Mr Socci identifies Islamic extremism as the main danger.

He complains that secular western governments, intellectuals and media organisations have played down the bloodbath because the persecution of Jews and Muslims, whether in the former Soviet Union or former Yugoslavia, was considered more newsworthy. "This global persecution of Christianity is still in progress but in most cases is ignored by the mass media and Christians in the west."

Tommaso Debenedetti, a cultural commentator, said the book was part of an attempt by Italy's right to deflect accusations of intolerance against immigrants and other minorities by casting itself as the victim of non-Christian and liberal forces. "The right is reversing the argument."

Breaking ranks with positive reviews which called the book "extraordinary", the Turin daily La Stampa said it was a provocation with questionable statistics and a flawed definition of martyr which included those killed for political reasons.